Preheat oven to 350 degrees F. In a blender or food processor, grind Fiber One® to a breadcrumb-like consistency. Melt butter in the microwave for 20 seconds.
Combine crumbs with melted butter and egg substitute and stir until well mixed. In an oven-safe pie dish sprayed lightly with nonstick spray, evenly distribute mixture, using your hands or a flat utensil to firmly press and form the crust. Press it into the edges and up along the sides of the dish.
Bake crust in oven for 10 minutes, then remove and allow to cool. In a medium-sized nonstick pot, combine cornstarch with cherry filling. Heat stovetop at medium heat, stirring often.
Once cherry mixture begins to bubble, lower heat and continue to stir for 3 minutes. Remove from heat and allow to cool for several minutes.
Evenly spoon cherry mixture into piecrust and allow pie to cool and set in the refrigerator for several hours before cutting and serving. Before serving, top each slice with a dollop of fat-free whipped topping.